The fatty acids as penetration enhancers of amino acids by ion pairing

Abstract

The influence of palmitic acid on n-octanol/water partition coefficient (log P) of selected amino acids, alanine, glycine, proline, hydroxyproline, seine, valine, threonine and lysine, was measured at a wide range of pH. A parabolic shape curve was obtained in every case (pH vs. Deltalog P), with maximum depending on the amino acid. In each case in the presence of palmitic acid, the apparent partition coefficient increased. To check the possible mechanism of extraction of amino acids into n-octanol phase in the presence of palmitate additionally, the influence of an amount of counter ion on partition coefficient of lysine was investigated. The results suggest that the enhanced partitioning of lysine results from the ion pair formation with palmitate. The ion pair stratum corneum-lipid membrane transport of the amino acids was investigated as well, using palmitate as a counter ion. The apparent permeability coefficients were enhanced significantly by palmitic acid at pH 7.4. As many substances (e.g. organic solvents, unsaturated fatty acids, etc.) are penetration enhancers which change the structure of intercellular lipid, the influence of palmitic acid on membrane was investigated. After pretreatment of membrane with palmitic acid, no changes in permeation of alanine were observed. Investigations suggest the enhanced permeation of amino acids via ion pairing. The method for prediction of pH in which the possibility of ion pairing is the highest was developed as well.

Liquid‐crystalline membrane permeation ability for selected nitro hair dyes

“…The preparation of model stratum corneum membrane was carried out according to the published method . A PET foil disc was put on a levelled glass plate and 0.25 cm 3 of Cerasome ® 9005 (Lipoid GmbH) lipids were applied onto a disc.…”

“…Permeation ability was investigated for selected dye series in side‐by‐side cells, with liposome membrane (as a model of stratum corneum ) trapped between two layers of semi‐permeable trek foil . The most important advantages of this technique are low cost and fast and repeatable experiments.…”

Artificial membranes as models in penetration investigations

“…Membranes were prepared according to the methods described in the literature . Lipid suspension (0.125 ml) was evenly applied to a polyethylene terephthalate filter discs (thickness 10 μm, diameter 25 mm, pore diameter 0.4 μm, pore surface density 7 × 10 7 /cm; Institute of Nuclear Chemistry and Technology, Warsaw, Poland).…”

Enhancement of exfoliating efficacy of L-carnitine with ion-pair method monitored by nuclear magnetic resonance spectroscopy

“…Although CAR has obvious benefits as a noble exfoliating agent, its application is limited by its poor transdermal penetration properties 22,23 . Even if amino acid derivatives are widely known to be safe relative to other chemicals, increasing the quantity of CAR to overcome its low penetration may cause safety issues.…”

“…We found that this could be best addressed using the ion-pair method. Furthermore, this is a simpler and cheaper method without the use of specific devices or modification of the substance structure but with a proper counter ion 22,23,28 . Therefore, we used the ion-pair method in this study.…”